The preliminary episodes and skirmishings, therefore, which went before the spiritual self-consciousness of America, will be treated here in outline only; only such events and persons as were the sources of subsequent important conditions will be drawn in light and shadow. This period of adventure and exploration is, it is true, rich in picturesque characters and romantic incident, but they have little organic relation to the history of the true America--which is the tracing of the development and embodiment of an abstract idea. They belong to Europe, whose life was present in them, though the men acted and the incidents occurred in a strange environment. They are attractive subjects of study in themselves, but have small pertinence to the present argument. Our aim will be to maintain an organic coherency. Still less can we linger in that impressive darkness before dawn which prevailed upon the continent before the advent of Columbus. The mystery which shrouds the origin and annals of the races which inhabited America previous to the European invasion has been assiduously investigated, but never dispelled. At first it was taken for granted that the "Indians," as the red men were ignorantly called, were the aboriginal denizens of the country. But the mounds, ruined cities, pottery and other remains since found in all parts of the land, concerning which the Indians could furnish no information, and which showed a state of civilization far in advance of theirs, were proof that a great people had existed here in the remote past, who had flourished and disappeared without leaving any trace whereby they could be accounted for or identified. They are an enigma compared with which the archeological problems of the Old World are an open book. We can form no conception of the conditions under which they lived, of their personal characteristics, of their language, habits, or religion. We cannot determine whether these forerunners of the Indians were one people in several stages of development, or several peoples in simultaneous occupation of the land. We can establish no trustworthy connection between them and any Asiatic races, and yet we are reluctant to believe them isolated from the rest of mankind. If they had dwelt here from their creation, why had they not progressed further in civilization?--and if they emigrated hither from another continent, why do their remains not indicate their source? By what agency did they perish, and when? The more keenly we strive to penetrate their mystery, the more perplexing does it appear; the further we investigate them, the more alien from anything we are or have known do they seem. Elusive as mist, and questionable as night, they form a suggestive background on which the vivid and energetic drama of our novel civilization stands out in sharp relief.